In the field of factory automation (FA), automatic control techniques using visual sensors are used widely. Such techniques include automatic processing in which an image of a target such as a workpiece is captured, the captured image undergoes image measurement such as pattern matching, and various control devices operate based on the measurement results.
A system including a visual sensor involves calibration of the measurement results transmitted from the visual sensor before outputting the resultant data to a controller. For example, Japanese Unexamined Patent Application Publication No. 2007-017424 (Patent Literature 1) describes a technique for automated positional alignment performed while measuring a reference mark on a workpiece mounted on an XYθ stage.
Designing or examining the system to be controlled with the above automatic control technique may need preliminary evaluation of the performance of the entire system. In response to this, a technique has been developed for virtually creating a system and simulating its operation. For example, Japanese Unexamined Patent Application Publication No. 2013-191128 (Patent Literature 2) describes a technique for integrated simulations of a mechanical system including a visual sensor in a real space corresponding to a virtual imaging unit. With the technique described in Patent Literature 2, a 3D simulator and a visual sensor simulator cooperate with each other to virtually generate captured images of a workpiece in a 3D space at predetermined timings. With the technique described in Patent Literature 2, a sample object arranged at a predetermined calibration position is virtually captured and used for calibration.
Japanese Unexamined Patent Application Publication No. 2015-136770 (Patent Literature 3) describes a technique for 3D modeling of a robot, a visual sensor, and a target in a virtual space in the same manner as in Patent Literature 2. With this technique, images of the target are virtually captured with the visual sensor to generate computer graphics images. The technique described in Patent Literature 3 eliminates calibration for adjustment between the robot and the visual sensor by calculating the positional relationship between the robot coordinate system and the sensor coordinate system.